polymers Review X-ray-Based Spectroscopic Techniques for Characterization of Polymer Nanocomposite Materials at a Molecular Level 1, 2,3, 1 4, 1, Dongwan Son y, Sangho Cho y , Jieun Nam , Hoik Lee * and Myungwoong Kim * 1 Department of Chemistry and Chemical Engineering, Inha University, Incheon 22212, Korea;
[email protected] (D.S.);
[email protected] (J.N.) 2 Materials Architecturing Research Center, Korea Institute of Science and Technology, Seoul 02792, Korea;
[email protected] 3 Division of Nano & Information Technology, KIST School, Korea University of Science and Technology, Seoul 02792, Korea 4 Research Institute of Industrial Technology Convergence, Korea Institute of Industrial Technology, Ansan 15588, Korea * Correspondence:
[email protected] (H.L.);
[email protected] (M.K.) These authors equally contributed to this work. y Received: 3 April 2020; Accepted: 23 April 2020; Published: 4 May 2020 Abstract: This review provides detailed fundamental principles of X-ray-based characterization methods, i.e., X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, and near-edge X-ray absorption fine structure, and the development of different techniques based on the principles to gain deeper understandings of chemical structures in polymeric materials. Qualitative and quantitative analyses enable obtaining chemical compositions including the relative and absolute concentrations of specific elements and chemical bonds near the surface of or deep inside the material of interest. More importantly, these techniques help us to access the interface of a polymer and a solid material at a molecular level in a polymer nanocomposite. The collective interpretation of all this information leads us to a better understanding of why specific material properties can be modulated in composite geometry.